This invention relates to gas mixers and, in particular, to mixers for forming combustible or explosive mixtures of gases.
Highly combustible mixtures of gases are used in a number of arts for a variety of purposes. As is known, different combinations of gases may be used depending upon the flame temperature desired. One of the hottest flames is obtained from a hydrogen/oxygen mixture. While producing a high flame temperature and being clean burning, this mixture must be carefully controlled.
Prior art mixers are internal mixers, i.e., the gases are mixed in the desired proportion inside the body of the mixer and the mixture fed by suitable conduit to the burner. With this arrangement, destructive flashbacks may occur in which the flame travels back through the conduit to the mixer, occasionally entering the mixer itself. In either event, the flashback is self-sustaining and often destroys the mixer. Aside from the obvious safety problems, flashback often results in appreciable downtime on the production equipment using the burner.
While a number of solutions have been proposed, such as using excess oxygen, running the mixture conduit vertically upward so that the water from combustion tends to extinguish the flame, or increasing the flow velocity of the gases, none has been satisfactory in reducing the incidence of flashback or destructive effects thereof.